Distribution control system, distribution system, distribution control method, and computer-readable storage medium

ABSTRACT

A distribution control system includes a generating unit configured to generate image data from content data; a converting unit configured to convert the image data into transmission data; a transmitting unit configured to transmit the transmission data to a plurality of communication terminals; and a creating/selecting unit configured to newly create the converting unit to be assigned to each of the communication terminals or select the converting unit out of converting units already created.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2013-054191 filedin Japan on Mar. 15, 2013; Japanese Patent Application No. 2013-053922filed in Japan on Mar. 15, 2013; Japanese Patent Application No.2014-028974 filed in Japan on Feb. 18, 2014; and Japanese PatentApplication No. 2014-028993 filed in Japan on Feb. 18, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a distribution control system, adistribution system, a distribution control method, and acomputer-readable storage medium, capable of transmitting data tocommunication terminals such as personal computers and electronicblackboards.

2. Description of the Related Art

With the recent widespread use of the Internet, cloud computing has beenused in various fields. Cloud computing is a service usage pattern inwhich users use services (cloud services) provided by a server on theInternet, using a communication terminal connected to the Internet andpay for the service.

Web content carried on the Internet tends to be enriched for the purposeof responding to various demands. As a result, accessing the enrichedcontent using a communication terminal for making use of servicesthrough the Internet involves a problem in that a load on thecommunication terminal is unfavorably high.

As a technology for reducing loads on communication terminals, there isa technology called thin client (refer to Japanese Patent ApplicationLaid-open No. 2007-221229, for example). This thin client technologyallows various applications to be executed on communication terminals ina web-based manner using an Internet environment.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

According to an embodiment, there is provided a distribution controlsystem that includes a generating unit configured to generate image datafrom content data; a converting unit configured to convert the imagedata into transmission data; a transmitting unit configured to transmitthe transmission data to a plurality of communication terminals; and acreating/selecting unit configured to newly create the converting unitto be assigned to each of the communication terminals or select theconverting unit out of converting units already created.

According to another embodiment, there is provided a distribution systemthat includes the distribution control system according to the aboveembodiment; and the communication terminals.

According to still another embodiment, there is provided a distributioncontrol method for converting image data generated from content datainto transmission data and transmitting the transmission data to aplurality of communication terminals. The distribution control methodincludes newly creating a converting unit configured to convert theimage data into the transmission data for each of the communicationterminals or select one out of converting units already created.

According to still another embodiment, there is provided anon-transitory computer-readable storage medium with an executableprogram stored thereon and executed by a computer for converting imagedata generated from content data into transmission data and transmittingthe transmission data to a plurality of communication terminals. Theprogram instructs the computer to perform: performing conversionprocessing that converts the image data into the transmission data; andnewly creating the conversion processing to be assigned to each of thecommunication terminals or selecting the conversion processing out ofpieces of conversion processing already created.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a distribution system according to anembodiment;

FIG. 2 is a conceptual view when a dongle is attached to a communicationterminal;

FIG. 3 is a conceptual diagram illustrating a basic distribution method;

FIG. 4 is a conceptual diagram of multicast;

FIG. 5 is a conceptual diagram of multidisplay;

FIG. 6 is a conceptual diagram of composite distribution using aplurality of communication terminals through a distribution controlsystem;

FIG. 7 is a hardware configuration diagram of a distribution controlsystem, a communication terminal, a terminal management system, and aweb server;

FIG. 8 is a hardware configuration diagram of the dongle;

FIG. 9 is a functional block diagram illustrating mainly the functionsof the distribution control system;

FIG. 10 is a functional block diagram illustrating mainly the functionsof the communication terminal;

FIG. 11 is a functional block diagram illustrating the functions of theterminal management system;

FIG. 12 is a conceptual view of a distribution destination selectionmenu screen;

FIG. 13 is a conceptual view of a terminal management table;

FIG. 14 is a conceptual view of an available terminal management table;

FIG. 15 is a detailed diagram of an encoder bridge unit;

FIG. 16 is a functional block diagram illustrating the functions of aconverter;

FIG. 17 is a sequence diagram illustrating basic distribution processingof the distribution control system;

FIG. 18 is a sequence diagram illustrating communication processingusing a plurality of communication terminals through the distributioncontrol system;

FIG. 19 is a sequence diagram illustrating the processing of timeadjustment;

FIG. 20 is a sequence diagram illustrating the processing of channeladaptive control on data transmitted from the distribution controlsystem to the communication terminal;

FIG. 21 is a sequence diagram illustrating the processing of channeladaptive control on data transmitted from the communication terminal tothe distribution control system;

FIG. 22 is a sequence diagram illustrating the processing ofmultidisplay;

FIG. 23 is a sequence diagram illustrating the processing ofmultidisplay;

FIG. 24 is a sequence diagram illustrating the processing ofmultidisplay;

FIG. 25 is a diagram for illustrating an example of frames distributedwhen a video encoder is switched so as to decrease a frame rate in thepresent embodiment; and

FIG. 26 is a diagram for illustrating an example of frames distributedwhen the video encoder is switched so as to increase the frame rate inthe present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Described below with reference to the accompanying drawings is adistribution system 1 according to an embodiment. Described below indetail is an invention that causes both a web browser (hereinafterreferred to as a “browser”) and an encoder to execute in cooperationwith each other in the cloud through cloud computing and transmits videodata, sound data, and the like to communication terminals.

In the following, “images” include a still image and a moving image.“Videos” basically mean moving images and also include moving imagesthat are stopped to be still images. A “still image (sound)” representsat least either one of a still image and sound. An “image (sound)”represents at least either one of an image and sound. A “video (sound)”represents at least either one of video and sound.

Outline of the Embodiment

Described with reference to FIG. 1 is an outline of the embodimentaccording to the present invention. FIG. 1 is a schematic diagram of adistribution system according to the present embodiment.

Outline of System Configuration

Described first is an outline of the configuration of the distributionsystem 1.

As illustrated in FIG. 1, the distribution system 1 according to thepresent embodiment includes a distribution control system 2, a pluralityof communication terminals (5 a to 5 f), a terminal management system 7,and a web server 8. In the following, any communication terminal amongthe communication terminals (5 a to 5 f) can be referred to as a“communication terminal 5”. The distribution control system 2, theterminal management system 7, and the web server 8 are all implementedby server computers.

The communication terminal 5 is a terminal used by a user who receivesservices of the distribution system 1. The communication terminal 5 a isa notebook personal computer (PC). The communication terminal 5 b is amobile terminal such as a smartphone or a tablet terminal. Thecommunication terminal 5 c is a multifunction peripheral/printer/product(MFP) in which the functions of copying, scanning, printing, and faxingare combined. The communication terminal 5 d is a projector. Thecommunication terminal 5 e is a TV (video) conference terminal having acamera, a microphone, and a speaker. The communication terminal 5 f isan electronic blackboard (whiteboard) capable of electronicallyconverting drawings drawn by a user or the like.

The communication terminal 5 is not only such terminals as illustratedin FIG. 1, but also may be devices communicable through a communicationnetwork such as the Internet, including a watch, a vending machine, acar navigation device, a game console, an air conditioner, a lightingfixture, a camera alone, a microphone alone, and a speaker alone.

The distribution control system 2, the communication terminal 5, theterminal management system 7, and the web server 8 can communicate witheach other through a communication network 9 including the Internet anda local area network (LAN). Examples of the communication network 9 mayinclude wireless communication networks such as 3rd Generation (3G),Worldwide Interoperability for Microwave Access (WiMAX), and Long-TermEvolution (LTE).

The communication terminal 5 d, for example, among the communicationterminals 5 does not have a function of communicating with the otherterminals or systems through the communication network 9. However, asillustrated in FIG. 2, a user inserts a dongle 99 into an interface suchas Universal Serial Bus (USB) or High-Definition Multimedia Interface(HDMI) of the communication terminal 5 d, thereby enabling it tocommunicate with the other terminals and systems. FIG. 2 is a conceptualview when the dongle is attached to the communication terminal.

The distribution control system 2 has a browser 20 in the cloud, andthrough the function of rendering in the browser 20, acquires a singleor a plurality of pieces of content data described in a certaindescription language and performs rendering on the content data, therebygenerating frame data including still image data such as bitmap datamade up of red, green, and blue (RGB) and sound data such as pulse codemodulation (PCM) data (i.e., still image (sound) data). The content datais data acquired from the web server 8, any communication terminal, andthe like and includes image (sound) data in Hypertext Markup Language(HTML) and Cascading Style Sheets (CSS), image (sound) data in MP4(MPEG-4), and sound data in Advanced Audio Coding (AAC).

The distribution control system 2 has an encoding unit 19 in the cloud,and the encoding unit 19 plays a role as an encoder, thereby convertingframe data as still image (sound) data into video (sound) data in thecompression coding format such as H.264 (MPEG-4 AVC), H.265, and MotionJPEG.

The terminal management system 7 performs login authentication on thecommunication terminal 5 and manages contract information and the likeof the communication terminal 5. The terminal management system 7 has afunction of a Simple Mail Transfer Protocol (SMTP) server fortransmitting e-mail. The terminal management system 7 can be embodiedas, for example, a virtual machine developed on a cloud service (IaaS:Infrastructure as a Service). It is desirable that the terminalmanagement system 7 be operated in a multiplexed manner to provideservice continuity in case of unexpected incidents.

The browser 20 enables real-time communication/collaboration (RTC). Thedistribution control system 2 includes the encoding unit 19 in FIG. 16described below, and the encoding unit 19 can perform real-time encodingon frame data output by the browser 20 and output video (sound) datagenerated through conversion compliant with the H.264 standard or thelike. As a result, the processing of the distribution control system 2is different from, for example, processing in a case in which nonreal-time video (sound) data recorded in a DVD is read and distributedby a DVD player.

Not only the distribution control system 2, but also the communicationterminal 5 may have a browser. In this case, updating the browser 20 ofthe distribution control system 2 eliminates the need to start up thebrowsers of the respective communication terminals 5.

Outline of Various Kinds of Distribution Methods

Described next is an outline of various distribution methods.

Basic Distribution

FIG. 3 is a conceptual diagram illustrating a basic distribution method.In the distribution system 1, as illustrated in FIG. 3, the browser 20of the distribution control system 2 acquires web content data [A] asimage (sound) data from the web server 8 and renders it, therebygenerating pieces of frame data [A] as still image (sound) data. Anencoder bridge unit 30 including the encoding unit 19 performs encodingand the like on the pieces of frame data [A], thereby converting theminto video (sound) data [A] in the compression coding format such asH.264 (an example of transmission data). The distribution control system2 distributes the video (sound) data [A] converted to the communicationterminal 5.

Thus, the distribution control system 2 can distribute even rich webcontent data to the communication terminal 5 while converting it fromthe web content data in HTML or the like into the compressed video(sound) data in H.264 or the like in the cloud. As a result, thecommunication terminal 5 can reproduce the web content smoothly withouttime and costs for adding the latest browser or incorporating ahigher-spec central processing unit (CPU), operating system (OS), randomaccess memory (RAM), and the like.

Future enrichment in web content will only require higher specificationsof the browser 20, the CPU, and the like in the distribution controlsystem 2 in the cloud, without the need for higher specifications of thecommunication terminal 5.

Applying the above distribution method, as illustrated in FIG. 4 to FIG.6, the distribution system 1 can also distribute web content data to aplurality of sites as video (sound) data. Described below aredistribution methods illustrated in FIG. 4 to FIG. 6.

Multicast

FIG. 4 is a conceptual diagram of multicast. As illustrated in FIG. 4,the single browser 20 of the distribution control system 2 acquires theweb content data [A] as image (sound) data from the web server 8 andrenders it, thereby generating pieces of frame data [A] as still image(sound) data. The encoder bridge unit 30 encodes the pieces of framedata [A], thereby converting them into video (sound) data. Thedistribution control system 2 then distributes the video (sound) data[A](an example of transmission data) to a plurality of communicationterminals (5 f 1, 5 f 2, 5 f 3).

Thus, the same video (sound) is reproduced at the sites. In this case,the communication terminals (5 f 1, 5 f 2, 5 f 3) do not need to havethe same level of display reproduction capability (e.g., the sameresolution). The distribution method like this is called, for example,“multicast”.

Multidisplay

FIG. 5 is a conceptual diagram of multidisplay. As illustrated in FIG.5, the single browser 20 of the distribution control system 2 acquiresweb content data [XYZ] as image (sound) data from the web server 8 andrenders it, thereby generating pieces of frame data [XYZ] as still image(sound) data. The encoder bridge unit 30 divides each frame data [XYZ]into a plurality of pieces of frame data ([X], [Y], [Z]) and thenencodes them, thereby converting them into a plurality of pieces ofvideo (sound) data ([X], [Y], [Z]). The distribution control system 2then distributes the video (sound) data [X](an example of transmissiondata) to the communication terminal 5 f 1. Similarly, the distributioncontrol system 2 distributes the video (sound) data [Y](an example oftransmission data) to the communication terminal 5 f 2 and distributesthe video (sound) data [Z](an example of transmission data) to thecommunication terminal 5 f 3.

Thus, for example, even for landscape web content [XYZ], video (sound)is reproduced by the communication terminals 5 in a divided manner. As aresult, when the communication terminals (5 f 1, 5 f 2, 5 f 3) areinstalled in a line, the same effect can be obtained as the reproductionof one piece of large video. In this case, the communication terminals(5 f 1, 5 f 2, 5 f 3) need to have the same level of displayreproduction capability (e.g., the same resolution). The distributionmethod like this is called, for example, “multidisplay”.

Composite Distribution

FIG. 6 is a conceptual diagram of composite distribution using aplurality of communication terminals through a distribution controlsystem. As illustrated in FIG. 6, the communication terminal 5 f 1 as anelectronic blackboard and a communication terminal 5 e 1 as ateleconference terminal are used at a first site (the right side in FIG.6), whereas at a second site (the left side in FIG. 6), thecommunication terminal 5 f 2 as an electronic blackboard and acommunication terminal 5 e 2 as a teleconference terminal are usedsimilarly. At the first site, an electronic pen P1 is used for drawingcharacters and the like with strokes on the communication terminal 5 f1. At the second site, an electronic pen P2 is used for drawingcharacters and the like with strokes on the communication terminal 5 f2.

At the first site, video (sound) data acquired by the communicationterminal 5 e 1 is encoded by an encoding unit 60 and is then transmittedto the distribution control system 2. After that, it is decoded by adecoding unit 40 of the distribution control system 2 and is then inputto the browser 20. Operation data indicating the strokes drawn on thecommunication terminal 5 f 1 with the electronic pen P1 (in this case,coordinate data on the display of the communication terminal 5 f 1 orthe like) is transmitted to the distribution control system 2 to beinput to the browser 20. Also at the second site, video (sound) dataacquired by the communication terminal 5 e 2 is encoded by the encodingunit 60 and is then transmitted to the distribution control system 2.After that, it is decoded by the decoding unit 40 of the distributioncontrol system 2 and is then input to the browser 20. Operation dataindicating the strokes drawn on the communication terminal 5 f 2 withthe electronic pen P2 (in this case, coordinate data on the display ofthe communication terminal 5 f 2 or the like) is transmitted to thedistribution control system 2 to be input to the browser 20.

The browser 20 acquires, for example, web content data [A] as abackground image displayed on the displays of the communicationterminals (5 f 1, 5 f 2) from the web server 8. The browser 20 combinesthe web content data [A], operation data ([p1], [p2]), and video (sound)content data ([E1], [E2]) and renders them, thereby generating pieces offrame data as still image (sound) data in which the pieces of contentdata ([A], [p1], [p2], [E1], [E2]) are arranged in a desired layout. Theencoder bridge unit 30 encodes the pieces of frame data, and thedistribution control system 2 distributes video (sound) data indicatingthe same content ([A], [p1], [p2], [E1], [E2]) to both sites. At thefirst site, thereby video ([A], [p1], [p2], [E1 (video part)], and [E2(video part)]) is displayed on the display of the communication terminal5 f 1, and sound [E2 (sound part)] is output from the speaker of thecommunication terminal 5 e 1. Also at the second site, the video ([A],[p1], [p2], [E1 (video part)], and [E2 (video part)]) is displayed onthe display of the communication terminal 5 f 2, and sound [E1 (soundpart)] is output from the speaker of the communication terminal 5 e 2.At the first site, the sound of the site itself [E1 (sound part)] is notoutput owing to an echo cancelling function of the communicationterminal 5 f 1. At the second site, the sound of the site itself [E2(sound part)] is not output owing to an echo cancelling function of thecommunication terminal 5 f 2.

Thus, at the first site and the second site, remote sharing processingcan be performed that shares the same information in real time at remotesites, thus making the distribution system 1 according to the presentembodiment effective in a teleconference or the like.

DETAILED DESCRIPTION OF THE EMBODIMENT

The following describes the embodiment in detail with reference to FIG.7 to FIG. 24.

Hardware Configuration of the Embodiment

Described first with reference to FIG. 7 and FIG. 8 is the hardwareconfiguration of the present embodiment. FIG. 7 is a hardwareconfiguration diagram of a distribution control system, a communicationterminal, a terminal management system, and a web server. FIG. 8 is ahardware configuration diagram of a dongle. Because the hardwareconfiguration relating to the communication of the communicationterminal is the same as part of the hardware configuration of thecommunication terminal, the description thereof will be omitted.

As illustrated in FIG. 7, the distribution control system 2 includes: aCPU 201 that controls the entire operation of the distribution controlsystem 2; a read-only memory (ROM) 202 that stores therein a programused for driving the CPU 201 such as IPL; a RAM 203 used as a work areaof the CPU 201; an HDD 204 that stores therein various kinds of datasuch as programs; a hard disk controller (HDC) 205 that controls thereading and writing of the various kinds of data from and into the HDD204 under the control of the CPU 201; a media drive 207 that controlsthe reading and writing of data from and into a storage medium 206 suchas a flash memory; a display 208 that displays various kinds ofinformation; an interface (I/F) 209 that transmits data through thecommunication network 9 and to which the dongle 99 is connected; akeyboard 211; a mouse 212; a microphone 213; a speaker 214; a graphicsprocessing unit (GPU) 215; and a bus line 220 such as an address bus ora data bus for electrically connecting the above components asillustrated in FIG. 7. As in the communication terminal 5 d as aprojector, the GPU may not be provided. Because the hardwareconfiguration of the terminal management system 7 and the web server 8is the same as the hardware configuration of the distribution controlsystem 2, the description thereof will be omitted.

Described next with reference to FIG. 8 is the hardware configuration ofthe dongle 99 illustrated in FIG. 2. As illustrated in FIG. 8, thedongle 99 includes: a CPU 91 that controls the entire operation of thedongle 99; a ROM 92 that stores therein a basic input/output program; aRAM 93 used as a work area of the CPU 91; an electrically erasable andprogrammable ROM (EEPROM) 94 that performs the reading and writing ofdata under the control of the CPU 91; a GPU 95; an interface I/F 96 forconnection to the I/F 209 of the communication terminal 5; an antenna 97a; a communication unit 97 that performs communications by ashort-distance wireless technology through the antenna 97 a; and a busline 90 such as an address bus or a data bus for electrically connectingthe above units. Examples of the short-distance wireless technologyinclude the Near Field Communication (NFC) standards, Bluetooth(registered trademark), Wireless Fidelity (WiFi), and ZigBee (registeredtrademark). Because the dongle 99 includes the GPU 95, even when no GPUis included as in the communication terminal 5 d, the communicationterminal 5 can perform calculation processing needed for graphicsdisplay with the dongle 99 attached as illustrated in FIG. 2.

Functional Configuration of the Embodiment

The functional configuration of the embodiment is described next withreference to FIG. 9 to FIG. 16.

Functional Configuration of the Distribution Control System

Described first with reference to FIG. 9 is the functional configurationof the distribution control system 2. FIG. 9 is a functional blockdiagram illustrating mainly the functions of the distribution controlsystem. FIG. 9 illustrates a functional configuration where thedistribution control system 2 distributes video (sound) data to thecommunication terminal 5 f 1, and the distribution control system 2 hasthe same functional configuration also where the distributiondestination is other than the communication terminal 5 f 1. Although thedistribution control system 2 includes a plurality of distributionengine servers, the following describes a case where a singledistribution engine server is included, in order to simplify thedescription.

As illustrated in FIG. 9, the distribution control system 2 hasfunctional components in FIG. 9 implemented by the hardwareconfiguration including the CPU 201 and the programs illustrated in FIG.7.

Specifically, the distribution control system 2 includes the browser 20,a transmitter/receiver 21, a browser management unit 22, a transmissionfirst-in first-out (FIFO) buffer 24, a time management unit 25, a timeacquisition unit 26, a channel adaptive controller 27, the encoderbridge unit 30, a transmitter/receiver 31, a reception FIFO 34, arecognition unit 35, a delay information acquisition unit 37 a, achannel adaptive controller 37 b, and the decoding unit 40. Thedistribution control system 2 further includes a storage unit 2000implemented by the HDD 204 illustrated in FIG. 7. This storage unit 2000stores therein recognition information (described below) output from therecognition unit 35 and sent through the browser management unit 22. Thecontent data acquired by the browser 20 can be temporarily stored in thestorage unit 2000 as a cache.

Among the above functional components, the browser 20 is a browser thatoperates within the distribution control system 2. The browser 20 iskept updated along with the enrichment of web content at all times. Thebrowser 20 includes Media Player, Flash Player, JavaScript (registeredtrademark), CSS, and HTML Renderer. JavaScript includes the standardizedproduct and one unique to the distribution system 1.

Media Player is a browser plug-in for reproducing multimedia files suchas video (sound) files within the browser 20. Flash Player is a browserplug-in for reproducing flash content within the browser 20. The uniqueJavaScript is a JavaScript group that provides the applicationprogramming interface (API) of services unique to the distributionsystem 1. CSS is a technology for efficiently defining the appearanceand style of web pages described in HTML. HTML Renderer is an HTMLrendering engine.

A renderer renders content data such as web content data as image(sound) data, thereby generating pieces of frame data as still image(sound) data. As illustrated in FIG. 6, the renderer is also a layoutengine that lays out a plurality of kinds of content ([A], [p1], [p2],[E1], [E2]).

The distribution system 1 according to the present embodiment providesthe browsers 20 within the distribution control system 2, and a cloudbrowser for use in a user session is selected from the browsers 20. Thefollowing describes a case where the single browser 20 is provided, inorder to simplify the description.

The transmitter/receiver 21 transmits and receives various kinds ofdata, various kinds of requests, various kinds of instructions, and thelike to and from the terminal management system 7 and the web server 8.For example, the transmitter/receiver 21 acquires web content data froma content site at the web server 8. The transmitter/receiver 21 outputsthe various kinds of data acquired from the terminal management system 7to the functional components within the distribution control system 2and controls the functional components within the distribution controlsystem 2 based on the various kinds of data, various kinds of requests,various kinds of instructions, and the like acquired from the terminalmanagement system 7. For example, for the browsers 20, thetransmitter/receiver 21 outputs a request for switching distributionpattern from the terminal management system 7, to the browser managementunit 22. The browser management unit 22 then controls switching from onebrowser to another browser among the browsers. Based on the request forswitching distribution from the terminal management system 7, thetransmitter/receiver 21 performs the switching of combinations of thecomponents within the encoder bridge unit 30 illustrated in FIG. 15 andFIG. 16.

The browser management unit 22 manages the browser 20. For example, thebrowser management unit 22 instructs the browser 20 to start up andexit, and numbers an encoder ID at startup or exit. The encoder ID isidentification information that the browser management unit 22 numbersin order to manage the process of the encoder bridge unit 30. Thebrowser management unit 22 numbers and manages a browser ID every timethe browser 20 is started up. The browser ID is identificationinformation that the browser management unit 22 numbers in order tomanage the process of the browser 20 to identify the browser 20.

The browser management unit 22 acquires various kinds of operation datafrom the communication terminal 5 through the transmitter/receiver 31and outputs them to the browser 20. The operation data is data generatedthrough operation events (operations through the keyboard 211, the mouse212, and the like, strokes with an electronic pen P and the like) on thecommunication terminal 5. When the communication terminal 5 providesvarious sensors such as a temperature sensor, a humidity sensor, and anacceleration sensor, the browser management unit 22 acquires sensorinformation that contains output signals of the sensors from thecommunication terminal 5 and outputs it to the browser 20. The browsermanagement unit 22 further acquires image (sound) data from therecognition unit 35 and outputs it to the browser 20, and acquiresrecognition information described below from the recognition unit 35 andstores it in the storage unit 2000. The browser management unit 22acquires video (sound) data from the reception FIFO buffer 34 andoutputs it to the browser 20.

The transmission FIFO 24 is a buffer that stores therein pieces of framedata as still image (sound) data generated by the browser 20.

The time management unit 25 manages time T unique to the distributioncontrol system 2.

The time acquisition unit 26 performs time adjustment processing inconjunction with a time controller 56 in the communication terminal 5described below. Specifically, the time acquisition unit 26 acquirestime information (T) indicating time T in the distribution controlsystem 2 from the time management unit 25, receives time information (t)indicating time t in the communication terminal 5 from the timecontroller 56 described below through the transmitter/receiver 31 and atransmitter/receiver 51, and transmits the time information (t) and thetime information (T) to the time controller 56.

The channel adaptive controller 27 calculates reproduction delay time Ubased on transmission delay time information (D) and calculatesoperation conditions such as the frame rate and the data resolution of aconverter 10 in the encoder bridge unit 30. This reproduction delay timeis time for delaying reproduction through the buffering of data untilbeing reproduced. In other words, the channel adaptive controller 27changes the operation of the encoder bridge unit 30 based on thetransmission delay time information (D) and the size of the data (e.g.,the number of bits or the number of bytes). The transmission delay timeinformation (D) indicates frequency distribution information based on aplurality of pieces of transmission delay time D1 acquired by a delayinformation acquisition unit 57 of the communication terminal 5. Thetransmission delay time D1 indicates time from the point when the video(sound) data is transmitted from the distribution control system 2 tothe point when it is received by the communication terminal 5, and isacquired from a reproduction controller 53.

The encoder bridge unit 30 outputs pieces of frame data as still image(sound) data generated by the browser 20 to the converter 10 in theencoder bridge unit 30 described below. In this case, the encoder bridgeunit 30 also operates based on the operation conditions calculated bythe channel adaptive controller 27. The encoder bridge unit 30 will bedescribed in more detail with reference to FIG. 15 and FIG. 16. FIG. 15is a detailed diagram of the encoder bridge unit. FIG. 16 is afunctional block diagram illustrating the functions of the converter.

As illustrated in FIG. 15, the encoder bridge unit 30 includes acreating/selecting unit 310, a selecting unit 320, and a plurality ofconverters (10 a, 10 b, 10 c) provided therebetween. Although the threeconverters are illustrated here, any number of them may be provided. Inthe following, any converter is referred to as a “converter 10”.

The converter 10 converts the data format of the pieces of frame data asstill image (sound) data generated by the browser 20 into a data formatof H.264 or the like allowing distribution of the data to thecommunication terminal 5 through the communication network 9. For thatpurpose, as illustrated in FIG. 16, the converter 10 includes a trimmingunit 11, a resizing unit 12, a dividing unit 13, and the encoding unit19. The trimming unit 11, the resizing unit 12, and the dividing unit 13do not perform any processing on sound data.

The trimming unit 11 performs processing to cut out part of a stillimage. The resizing unit 12 changes the scale of a still image. Thedividing unit 13 divides a still image as illustrated in FIG. 5.

The encoding unit 19 encodes the pieces of frame data as still image(sound) data generated by the browser 20, thereby converting them todistribute video (sound) data to the communication terminal 5 throughthe communication network 9. When the video is not in motion (when thereis no inter-frame change), a skip frame is thereafter inserted until thevideo moves to save a band.

When sound data is generated together with still image data byrendering, both pieces of data are encoded, and when only sound data isgenerated, only encoding is performed to compress data without trimming,resizing, and dividing.

The creating/selecting unit 310 creates a new converter 10 or selectspieces of frame data as still image (sound) data to be input to aconverter 10 that is already generated. In the creation, thecreating/selecting unit 310 creates a converter 10 capable of conversionaccording to the capability of the communication terminal 5 to reproducevideo (sound) data. In the selection, a converter 10 that is alreadygenerated is selected. For example, in starting distribution to thecommunication terminal 5 b in addition to distribution to thecommunication terminal 5 a, the same video (sound) data as video (sound)data being distributed to the communication terminal 5 a may bedistributed to the communication terminal 5 b. In such a case,furthermore, when the communication terminal 5 b has the same level ofcapability as the capability of the communication terminal 5 a toreproduce video (sound) data, the creating/selecting unit 310 uses theconverter 10 a that is already created for the communication terminal 5a, without creating a new converter 10 b for the communication terminal5 b (the sharing of the encoder). However, when at least either onecommunication terminal 5 of the communication terminals 5 a and 5 b hasbecome not to satisfy a condition for sharing the converter 10 a, thecreating/selecting unit 310 creates a new converter 10 for thecommunication terminal 5 that has become not to satisfy the condition(the division of the encoder). The following describes conditions andcontrol in the sharing/division of the encoder (the converter 10).

The selecting unit 320 selects a desired one from the converters 10 thatare already generated. The selection by the creating/selecting unit 310and the selecting unit 320 allows distribution in various patterns asillustrated in FIG. 6.

The transmitter/receiver 31 transmits and receives various data,requests, and the like to and from the communication terminal 5. Thistransmitter/receiver 31 transmits various data, requests, and the liketo the communication terminal 5 through the communication network 9 fromthe cloud, thereby allowing the distribution control system 2 todistribute various data, requests, and the like to the communicationterminal 5. For example, in the login processing of the communicationterminal 5, the transmitter/receiver 31 transmits, to thetransmitter/receiver 51 of the communication terminal 5, authenticationscreen data for prompting a user for a login request. Thetransmitter/receiver 31 also performs data transmission and datareception to and from user applications of the communication terminal 5and device applications of the communication terminal 5 by a protocolunique to the distribution system 1 through a Hypertext TransferProtocol over Secure Socket Layer (HTTPS) server. This unique protocolis an HTTPS-based application layer protocol for transmitting andreceiving data in real time without being interrupted between thedistribution control system 2 and the communication terminal. Thetransmitter/receiver 31 also performs transmission response control,real-time data creation, command transmission, reception responsecontrol, reception data analysis, and gesture conversion.

The transmission response control is processing to manage an HTTPSsession for downloading requested from the communication terminal 5 inorder to transmit data from the distribution control system 2 to thecommunication terminal 5. The response of the HTTPS session fordownloading does not end immediately and holds for a certain period oftime (one to several minutes). The transmitter/receiver 31 dynamicallywrites data to be sent to the communication terminal 5 in the body partof the response. In order to eliminate costs for reconnection, anotherrequest is allowed to reach from the communication terminal before theprevious session ends. By putting the transmitter/receiver 31 on standbyuntil the previous request is completed, overhead can be eliminated evenwhen reconnection is performed.

The real-time data creation is processing to give a unique header to thedata of compressed video (and a compressed sound) generated by theencoding unit 19 in FIG. 16 and write it in the body part of HTTPS.

The command transmission is processing to generate command data to betransmitted to the communication terminal 5 and write it in the bodypart of HTTPS directed to the communication terminal 5.

The reception response control is processing to manage an HTTPS sessionrequested from the communication terminal 5 in order for thedistribution control system 2 to receive data from the communicationterminal 5. The response of this HTTPS session does not end immediatelyand is held for a certain period of time (one to several minutes). Thecommunication terminal 5 dynamically writes data to be sent to thetransmitter/receiver 31 of the distribution control system 2 in the bodypart of the request.

The reception data analysis is processing to analyze the datatransmitted from the communication terminal 5 by type and deliver thedata to a necessary process.

The gesture conversion is processing to convert a gesture event input tothe communication terminal 5 f as the electronic blackboard by a userwith an electronic pen or in handwriting into data in a formatreceivable by the browser 20.

The reception FIFO 34 is a buffer that stores therein video (sound) datadecoded by the decoding unit 40.

The recognition unit 35 performs processing on image (sound) datareceived from the communication terminal 5. Specifically, for example,the recognition unit 35 recognizes the face, age, sex, and the like of ahuman or animal based on images taken by a camera 62 for signage. In aworkplace, the recognition unit 35 performs name tagging by facerecognition and processing of replacing a background image based onimages taken by the camera 62. The recognition unit 35 storesrecognition information indicating the recognized details in the storageunit 2000. The recognition unit 35 achieves speeding up by performingprocessing with a recognition expansion board.

The delay information acquisition unit 37 a is used for the processingof upstream channel adaptive control and corresponds to the delayinformation acquisition unit 57 of the communication terminal 5 for usein the processing of downstream channel adaptive control. Specifically,the delay information acquisition unit 37 a acquires transmission delaytime information (d1) indicating transmission delay time d1 from thedecoding unit 40 and holds it for a certain period of time, and when aplurality of pieces of transmission delay time information (d1) areacquired, outputs to the channel adaptive controller 37 b transmissiondelay time information (d) indicating frequency distribution informationbased on a plurality of pieces of transmission delay time d1. Thetransmission delay time information (d1) indicates transmission delaytime indicating time from the point when the video (sound) data istransmitted from the communication terminal 5 to the point when it isreceived by the distribution control system 2.

The channel adaptive controller 37 b is used for the processing of theupstream channel adaptive control and corresponds to the channeladaptive controller 27 for use in the processing of the downstreamchannel adaptive control. Specifically, the channel adaptive controller37 b calculates the operation conditions of the encoding unit 60 of thecommunication terminal 5 based on the transmission delay timeinformation (d). The channel adaptive controller 37 b transmits achannel adaptive control signal indicating operation conditions such asa frame rate and data resolution to the encoding unit 60 of thecommunication terminal 5 through the transmitter/receiver 31 and thetransmitter/receiver 51.

The decoding unit 40 decodes the video (sound) data transmitted from thecommunication terminal 5. The decoding unit 40 also outputs thetransmission delay time information (d1) indicating transmission delaytime d1 to the delay information acquisition unit 37 a.

Functional Configuration of Communication Terminal

The functional configuration of the communication terminal 5 isdescribed with reference to FIG. 10. FIG. 10 is a functional blockdiagram illustrating mainly the functions of the communication terminal.The communication terminal 5 is a terminal serving as an interface for auser to perform a login to the distribution system 1, start and stop thedistribution of video (sound) data, and the like.

As illustrated in FIG. 10, the communication terminal 5 has functionalcomponents in FIG. 10 implemented by the hardware configurationincluding the CPU 201 and the programs illustrated in FIG. 7. When thecommunication terminal 5 becomes communicable with the other terminalsand systems through the communication network 9 by the insertion of thedongle 99 as illustrated in FIG. 2, the communication terminal 5 has thefunctional components in FIG. 10 implemented by the hardwareconfiguration and the programs illustrated in FIG. 7 and FIG. 8.

Specifically, the communication terminal 5 includes a decoding unit 50,the transmitter/receiver 51, an operating unit 52, the reproductioncontroller 53, a rendering unit 55, the time controller 56, the delayinformation acquisition unit 57, a display unit 58, and the encodingunit 60. The communication terminal 5 further includes a storage unit5000 implemented by the RAM 203 illustrated in FIG. 7. This storage unit5000 stores therein time difference information (Δ) indicating a timedifference Δ described below and time information (t) indicating time tin the communication terminal 5.

The decoding unit 50 decodes video (sound) data distributed from thedistribution control system 2 and output from the reproductioncontroller 53.

The transmitter/receiver 51 transmits and receives various data,requests, and the like to and from the transmitter/receiver 31 of thedistribution control system 2 and a transmitter/receiver 71 a of theterminal management system 7. For example, in the login processing ofthe communication terminal 5, the transmitter/receiver 51 performs alogin request to the transmitter/receiver 71 of the terminal managementsystem 7 in response to the startup of the communication terminal 5 bythe operating unit 52.

The operating unit 52 performs processing to receive operations input bya user, such as input and selection with a power switch, a keyboard, amouse, the electronic pen P, and the like, and transmits them asoperation data to the browser management unit 22 of the distributioncontrol system 2.

The reproduction controller 53 buffers the video (sound) data (a packetof real-time data) received from the transmitter/receiver 51 and outputsit to the decoding unit 50 with the reproduction delay time U taken intoaccount. The reproduction controller 53 also calculates the transmissiondelay time information (D1) indicating transmission delay time D1, andoutputs the transmission delay time information (D1) to the delayinformation acquisition unit 57. The transmission delay time information(D1) indicates time from the point when the video (sound) data istransmitted from the distribution control system 2 to the point when itis received by the communication terminal 5.

The rendering unit 55 renders the data decoded by the decoding unit 50.

The time controller 56 performs time adjustment processing inconjunction with the time acquisition unit 26 of the distributioncontrol system 2. Specifically, the time controller 56 acquires timeinformation (t) indicating time t in the communication terminal 5 fromthe storage unit 5000. The time controller 56 issues a request for timeinformation (T) indicating time T in the distribution control system 2to the time acquisition unit 26 of the distribution control system 2through the transmitter/receiver 51 and the transmitter/receiver 31.

In this case, the time information (t) is transmitted concurrently withthe request for the time information (T).

The delay information acquisition unit 57 acquires from the reproductioncontroller 53 the transmission delay time information (D1) indicatingtransmission delay time D1 and holds it for a certain period of time,and when a plurality of pieces of transmission delay time information(D1) are acquired, outputs transmission delay time information (D)indicating frequency distribution information based on a plurality ofpieces of transmission delay time D1 to the channel adaptive controller27 through the transmitter/receiver 51 and the transmitter/receiver 31.The transmission delay time information (D) is transmitted, for example,once in a hundred frames.

The display unit 58 reproduces the data rendered by the rendering unit55.

The encoding unit 60 transmits video (sound) data [E] that is acquiredfrom a built-in microphone 213 or the camera 62 and a microphone 63 thatare externally attached, and is encoded; time information (t₀) thatindicates the current time t₀ in the communication terminal 5 and isacquired from the storage unit 5000; and the time difference information(Δ) that indicates the time difference Δ in between the distributioncontrol system 2 and the communication terminal 5 and is acquired fromthe storage unit 5000, to the decoding unit 40 of the distributioncontrol system 2 through the transmitter/receiver 51 and thetransmitter/receiver 31. The encoding unit 60 changes the operationconditions of the encoding unit 60 based on the operation conditionsindicated by the channel adaptive control signal received from thechannel adaptive controller 37 b. The encoding unit 60, in accordancewith the new operation conditions, transmits the video (sound) data [E]that is acquired from the camera 62 and the microphone 63 and isencoded; the time information (t₀) that indicates the current time t₀ inthe communication terminal 5 and is acquired from the storage unit 5000;and the time difference information (Δ) that indicates the timedifference Δ and is acquired from the storage unit 5000, to the decodingunit 40 of the distribution control system 2 through thetransmitter/receiver 51 and the transmitter/receiver 31.

The built-in microphone 213, the externally attached camera 62 andmicrophone 63, and the like are examples of an inputting unit and aredevices that need encoding and decoding. The inputting unit may outputtouch data and smell data in addition to video (sound) data.

The inputting unit includes various sensors such as a temperaturesensor, a direction sensor, an acceleration sensor, and the like.

Functional Configuration of the Terminal Management System

The functional configuration of the terminal management system 7 isdescribed with reference to FIG. 11. FIG. 11 is a functional blockdiagram illustrating the functions of the terminal management system.

As illustrated in FIG. 11, the terminal management system 7 hasfunctional components in FIG. 11 implemented by the hardwareconfiguration including the CPU 201 and the programs illustrated in FIG.7.

Specifically, the terminal management system 7 includes thetransmitter/receiver 71 a, a transmitter/receiver 71 b, and anauthentication unit 75. The terminal management system 7 furtherincludes a storage unit 7000 implemented by the HDD 204 illustrated inFIG. 7. The storage unit 7000 stores therein distribution destinationselection menu data, a terminal management table 7010, and an availableterminal management table 7020.

The distribution destination selection menu is data indicating such adestination selection menu screen as illustrated in FIG. 12.

As illustrated in FIG. 13, the terminal management table 7010 managesthe terminal ID of the communication terminal 5, a user certificate,contract information when a user uses the services of the distributionsystem 1, the terminal type of the communication terminal 5, settinginformation indicating the home uniform resource locators (URLs) of therespective communication terminals 5, the execution environmentinformation of the communication terminals 5, a shared ID, installationposition information, and display name information in association witheach other. The execution environment information includes “favorites”,“previous Cookie information”, and “cache file” of each communicationterminal 5, which are sent to the distribution control system 2 togetherwith the setting information after the login of the communicationterminal 5 and are used for performing an individual service on thecommunication terminal 5.

The shared ID is an ID that is used when each user distributes the samevideo (sound) data as video (sound) data being distributed to his/herown communication terminal 5 to the other communication terminals 5,thereby performing remote sharing processing, and is identificationinformation that identifies the other communication terminals and theother communication terminal group. For example, the shared ID of theterminal ID “t006” is “v006”, the shared ID of the terminal ID “t007” is“v006”, and the shared ID of the terminal ID “t008” is “v006”. When thecommunication terminal 5 a with the terminal ID “t001” issues a requestfor remote sharing processing with the communication terminals (5 f 1, 5f 2, 5 f 3) with the terminal ID “v006”, the distribution control system2 distributes the same video (sound) data as video (sound) data beingdistributed to the communication terminals 5 a to the communicationterminals (5 f 1, 5 f 2, 5 f 3). However, when the communicationterminals 5 a and the communication terminals (5 f 1, 5 f 2, 5 f 3) aredifferent in the resolution of the display unit 58, the distributioncontrol system 2 distributes the video (sound) data accordingly.

As illustrated in FIG. 5, for example, the installation positioninformation indicates an installation position when the communicationterminals (5 f 1, 5 f 2, 5 f 3) are arranged side by side. The displayname information is information indicating the details of the displayname in the distribution destination selection menu illustrated in FIG.12.

The available terminal management table 7020 manages, in associationwith each terminal ID, a shared ID indicating a communication terminalor a communication terminal group with which the communication terminal5 indicated by the terminal ID can perform remote sharing processing.

The functional components are described with reference to FIG. 11.

The transmitter/receiver 71 a transmits and receives various data,requests, and the like to and from the communication terminal 5. Forexample, the transmitter/receiver 71 a receives a login request from thetransmitter/receiver 51 of the communication terminal 5 and transmits anauthentication result of the login request to the transmitter/receiver51.

The transmitter/receiver 71 b transmits and receives various data,requests, and the like to and from the distribution control system 2.For example, the transmitter/receiver 71 b receives a request for thedata of the distribution destination selection menu from thetransmitter/receiver 21 of the distribution control system 2 andtransmits the data of the distribution destination selection menu to thetransmitter/receiver 21.

The authentication unit 75 searches the terminal management table 7010based on the terminal ID and the user certificate received from thecommunication terminal 5, thereby determining whether there is the samecombination of a terminal ID and a user certificate, therebyauthenticating the communication terminal 5.

Operations and Processing of the Embodiment

Operations and pieces of processing of the present embodiment aredescribed with reference to FIG. 17 to FIG. 24. These pieces ofprocessing are performed by the CPUs of the distribution control system2, the communication terminal 5, the terminal management system 7, andthe web server 8 in accordance with the respective programs storedtherein.

Basic Distribution Processing

Specific distribution processing in the basic distribution methodillustrated in FIG. 3 is described with reference to FIG. 17. FIG. 17 isa sequence diagram illustrating the basic distribution processing of thedistribution control system. Although described here is a case ofissuing a login request through the communication terminal 5 a, a loginmay be performed through the communication terminal 5 other than thecommunication terminal 5 a.

As illustrated in FIG. 17, when a user turns on the communicationterminal 5 a, the transmitter/receiver 51 of the communication terminal5 a issues a login request to the transmitter/receiver 71 a of theterminal management system 7 (Step S21). The transmitter/receiver 71 areceives the login request. This login request includes the terminal IDand the user certificate of the communication terminal 5 a. Theauthentication unit 75 then acquires the terminal ID and the usercertificate of the communication terminal 5 a.

The authentication unit 75 searches the terminal management table 7010based on the terminal ID and the user certificate, thereby determiningwhether there is the same combination of a terminal ID and a usercertificate, thereby authenticating the communication terminal 5 a (StepS22). The following describes a case where the same combination of aterminal ID and a user certificate is present in the terminal managementtable 7010, that is, where the communication terminal 5 a is determinedas a valid terminal in the distribution system 1.

The transmitter/receiver 71 a of the terminal management system 7transmits the IP address of the distribution control system 2 to thetransmitter/receiver 51 of the communication terminal 5 a (Step S23).The IP address of the distribution control system 2 is acquired from thedistribution control system 2 by the terminal management system 7 and isstored in the storage unit 7000 in advance.

The transmitter/receiver 71 b of the terminal management system 7 issuesa startup request of the browser 20 to the transmitter/receiver 21 ofthe distribution control system 2 (Step S24). The transmitter/receiver21 receives the startup request of the browser 20. The browsermanagement unit 22 starts up the browser 20 based on the startup requestreceived by the transmitter/receiver 21 (Step S25).

The creating/selecting unit 310 of the encoder bridge unit 30 createsthe converter 10 in accordance with the capability of the communicationterminal 5 a to reproduce video (sound) data (the resolution of thedisplay and the like) and the type of content (Step S26). Next, thetransmitter/receiver 21 issues a request for content data [A] to the webserver 8 in accordance with an instruction by the browser 20 (Step S27).In response thereto, the web server 8 reads the requested content data[A] from its own storage unit (not illustrated) (Step S28). The webserver 8 then transmits the content data [A] to the transmitter/receiver21 of the distribution control system 2 (Step S29).

The browser 20 renders the content data [A] received by thetransmitter/receiver 21, thereby generating pieces of frame data asstill image (sound) data and outputs them to the transmission FIFO 24(Step S30). The converter 10 encodes the pieces of frame data stored inthe transmission FIFO 24, thereby converting them into video (sound)data [A] to be distributed to the communication terminal 5 a (Step S31).

The transmitter/receiver 31 transmits the video (sound) data [A] to thetransmitter/receiver 51 of the communication terminal 5 a (Step S32).The transmitter/receiver 51 of the communication terminal 5 a receivesthe video (sound) data [A] and outputs it to the reproduction controller53.

In the communication terminal 5 a, the decoding unit 50 acquires thevideo (sound) data [A] from the reproduction controller 53 and decodesit (Step S33). After that, a speaker 61 reproduces sound based ondecoded sound data [A], and the display unit 58 reproduces video basedon video data [A] acquired from the decoding unit 50 and rendered by therendering unit 55 (Step S34).

Processing of Composite Distribution Using a Plurality of CommunicationTerminals

The following describes communication processing using a plurality ofcommunication terminals through the distribution control system withreference to FIG. 18. FIG. 18 is a sequence diagram illustratingdistribution processing using a plurality of communication terminalsthrough the distribution control system. Described here is specificprocessing for the communication terminals 5 in the pattern illustratedin FIG. 6. Because the processing here includes login processing,browser startup, and the like similar to Steps S21 to S29, descriptionstarts with the processing corresponding to Step S29.

As illustrated in FIG. 18, the transmitter/receiver 21 of thedistribution control system 2 receives content data [A] from the webserver 8 (Step S41). The browser 20 renders the content data [A],thereby generating pieces of frame data as still image (sound) data andoutputs them to the transmission FIFO 24 (Step S42).

When the encoding unit 60 of the communication terminal 5 f 1 receivesthe input of content data as video (sound) data [E] from the camera 62and the microphone 63 (Step S43), the encoding unit 60 encodes thecontent data [E](Step S44). The transmitter/receiver 51 transmits thecontent data [E] encoded by the encoding unit 60 to thetransmitter/receiver 31 of the distribution control system 2 (Step S45).The transmitter/receiver 31 of the distribution control system 2receives the content data [E].

The decoding unit 40 of the distribution control system 2 decodes thecontent data [E] received by the transmitter/receiver 31 and outputs itto the reception FIFO 34 (Step S46). The browser 20 renders the contentdata [E] stored in the reception FIFO 34, thereby generating frame data[E] as still image (sound) data and outputs it to the transmission FIFO24 (Step S47). In this case, the browser 20 outputs the data in a layoutin which the content data [E] is combined with the content data [A]already acquired.

In addition, when the operating unit 52 of the communication terminal 5f 1 receives the input of a stroke operation with the electronic pen P1(Step S48), the transmitter/receiver 51 transmits operation data [p]indicating the details of the stroke operation received by the operatingunit 52 to the transmitter/receiver 31 of the distribution controlsystem 2 (Step S49). The transmitter/receiver 31 of the distributioncontrol system 2 receives the operation data [p]. The browser managementunit 22 outputs the operation data [p] received by thetransmitter/receiver 31 to the browser 20.

The browser 20 renders the operation data [p], thereby generating framedata [p] as still image (sound) data and outputs it to the transmissionFIFO 24 (Step S50). In this case, the browser 20 outputs the data in alayout in which the operation data [p] is combined with the content data([A], [E]) already acquired.

The converter 10 encodes pieces of frame data ([A], [E], [p]) as stillimage (sound) data stored in the transmission FIFO 24, therebyconverting them into video (sound) data ([A], [E], [p]) to bedistributed to the communication terminal 5 f 1 (Step S51).

The transmitter/receiver 31 acquires the encoded video (sound) data([A], [E], [p]) from the encoder bridge unit 30 including the converter10 and transmits it to the transmitter/receiver 51 of the communicationterminal 5 f 1 (Step S52-1). The transmitter/receiver 51 of thecommunication terminal 5 f 1 receives the video (sound) data ([A], [E],[p]), and the reproduction controller 53 of the communication terminal 5f 1 acquires the video (sound) data ([A], [E], [p]) from thetransmitter/receiver 51. In the communication terminal 5 f 1, thedecoding unit 50 acquires the video (sound) data ([A], [E], [p]) fromthe reproduction controller 53 and decodes it (Step S53-1). After that,the speaker 61 reproduces sound based on decoded sound data ([A], [E]),and the display unit 58 reproduces video based on video data ([A], [E],[p]) acquired from the decoding unit 50 and rendered by the renderingunit 55 (Step S54-1).

For the communication terminal 5 f 2, as is the case with Step S52-1,the transmitter/receiver 31 acquires the encoded video (sound) data([A], [E], [p]) from the encoder bridge unit 30 and transmits it to thetransmitter/receiver 51 of the communication terminal 5 f 2 (StepS52-2). The reproduction controller 53 of the communication terminal 5 f2 acquires the video (sound) data ([A], [E], [p]). In the communicationterminal 5 f 1, the decoding unit 50 acquires the video (sound) data([A], [E], [p]) from the reproduction controller 53 and decodes it (StepS53-2). After that, the speaker 61 reproduces sound based on decodedsound data ([A], [E]), and the display unit 58 reproduces video based onvideo data ([A], [E], [p]) acquired from the decoding unit 50 andrendered by the rendering unit 55 (Step S54-2).

Thus, the same video (sound) as the video (sound) output to thecommunication terminal 5 f 1 is output also to the communicationterminal 5 f 2.

Processing of Time Adjustment

The processing of time adjustment is described with reference to FIG.19. FIG. 19 is a sequence diagram illustrating the processing of timeadjustment.

In order to acquire time indicating when the transmitter/receiver 51issues a request for the time information (T) to the distributioncontrol system 2, the time controller 56 of the communication terminal 5acquires time information (t_(s)) in the communication terminal 5 fromthe storage unit 5000 (Step S81). The transmitter/receiver 51 issues arequest for the time information (T) to the transmitter/receiver 31(Step S82). In this case, the time information (t_(s)) is transmittedconcurrently with the request for the time information (T).

In order to acquire time indicating when the transmitter/receiver 31received the request at Step S82, the time acquisition unit 26 of thedistribution control system 2 acquires time information (T_(r)) in thedistribution control system 2 from the time management unit 25 (StepS83). In order to acquire time indicating when the transmitter/receiver31 responds to the request at Step S82, the time acquisition unit 26further acquires time information (T_(s)) in the distribution controlsystem 2 from the time management unit 25 (Step S84). Thetransmitter/receiver 31 then transmits the time information (t_(s),T_(r), T_(s)) to the transmitter/receiver 51.

In order to acquire time indicating when the transmitter/receiver 51received the response at Step S85, the time controller 56 of thecommunication terminal 5 acquires time information (t_(r)) in thecommunication terminal 5 from the storage unit 5000 (Step S86).

The time controller 56 of the communication terminal 5 calculates thetime difference Δ between the distribution control system 2 and thecommunication terminal 5 (Step S87). This time difference Δ is given byEquation (1) below.Δ=((T _(r) +T _(s))/2)−((t _(r) +t _(s))/2)  (1)

The time controller 56 stores the time difference information (Δ)indicating the time difference Δ in the storage unit 5000 (Step S88).The series of processing of time adjustment is performed, for example,regularly every minute.

Processing of Downstream Channel Adaptive Control

Described next with reference to FIG. 20 is the processing of channeladaptive control on data transmitted from the distribution controlsystem 2 to the communication terminal 5 (downstream). FIG. 20 is asequence diagram illustrating the processing of channel adaptive controlon data transmitted from the distribution control system to thecommunication terminal.

First, the channel adaptive controller 27 of the distribution controlsystem 2 calculates reproduction delay time information (U) indicatingreproduction delay time U for delaying reproduction by buffering untilthe reproduction controller 53 of the communication terminal 5reproduces video (sound) data, and outputs the reproduction delay timeinformation (U) to the encoder bridge unit 30 (Step S101).

The transmitter/receiver 31 then acquires the reproduction delay timeinformation (U) from the encoder bridge unit 30 and transmits it to thetransmitter/receiver 51 of the communication terminal 5 (Step S102). Thetransmitter/receiver 51 of the communication terminal 5 receives thereproduction delay time information (U). The encoder bridge unit 30 addstime information (T₀) indicating time T₀ acquired from the timemanagement unit 25, as a time stamp to the video (sound) data [A]acquired from the transmission FIFO 24 and encoded, for example (StepS103). The transmitter/receiver 31 transmits the video (sound) data andthe time information (T₀) of the distribution control system 2 to thetransmitter/receiver 51 of the communication terminal 5 (Step S104). Thetransmitter/receiver 51 of the communication terminal 5 receives thetime information (T₀) of the distribution control system 2 and outputsthe video (sound) data and the time information (T₀) to the reproductioncontroller 53.

In the communication terminal 5, based on the reproduction delay timeinformation (U) acquired at Step S102, the time information (T₀)acquired at Step S104, and the time difference information (Δ) stored inthe storage unit 5000 at Step S88, the reproduction controller 53 waitsuntil the time (T₀+U−Δ) in the communication terminal 5 and then outputsthe video (sound) data acquired at Step S104 to the decoding unit 50.This causes the speaker 61 to output sound and the display unit 58 toreproduce video through the rendering unit 55 (Step S105). This causesonly video (sound) data received by the communication terminal 5 withinthe range of the reproduction delay time U given by Equation (2) belowto be reproduced, while video (sound) data out of the range is delayedexcessively and is deleted without being reproduced.U≧(t ₀+Δ)−T ₀  (2)

The reproduction controller 53 reads the current time t₀ in thecommunication terminal 5 from the storage unit 5000 (Step S106). Thistime t₀ indicates time in the communication terminal 5 when thecommunication terminal 5 received video (sound) data from thedistribution control system 2. The reproduction controller 53 furtherreads the time difference information (Δ) indicating the time differenceΔ stored at Step S86 in the storage unit 5000 (Step S107). Thereproduction controller 53 then calculates the transmission delay timeD1 indicating time from the point when the video (sound) data istransmitted from the distribution control system 2 to the point when itis received by the communication terminal 5 (Step S108). Thiscalculation is performed with Equation (3) below; when the communicationnetwork 9 becomes congested, the transmission delay time D1 becomeslonger.D1=(t ₀+Δ)−T ₀  (3)

The delay information acquisition unit 57 acquires transmission delaytime information (D1) indicating the transmission delay time D1 from thereproduction controller 53 and holds it for a certain period of time,and when a plurality of pieces of transmission delay time information(D1) are acquired, outputs to the transmitter/receiver 51 thetransmission delay time information (D) indicating frequencydistribution information based on a plurality of pieces of transmissiondelay time D1 (Step S109). The transmitter/receiver 51 transmits thetransmission delay time information (D) to the transmitter/receiver 31of the distribution control system 2 (Step S110). Thetransmitter/receiver 31 of the distribution control system 2 receivesthe transmission delay time information (D) and outputs the transmissiondelay time information (D) to the channel adaptive controller 27.

The channel adaptive controller 27 of the distribution control system 2newly calculates reproduction delay information U′ based on thetransmission delay time information (D) and calculates the operationconditions such as the frame rate and the data resolution of theconverter 10 and outputs them to the encoder bridge unit 30 (Step S111).In other words, the channel adaptive controller 27 changes the operationof the encoder bridge unit 30 based on the transmission delay timeinformation (D) and the size of the data (e.g., the number of bits orthe number of bytes).

The transmitter/receiver 31 acquires reproduction delay time information(U′) indicating the new reproduction delay time U′ calculated at StepS111 from the encoder bridge unit 30 and transmits the reproductiondelay time information (U′) to the transmitter/receiver 51 of thecommunication terminal 5 (Step S112). The transmitter/receiver 51 of thecommunication terminal 5 receives the reproduction delay timeinformation (U′).

The converter 10 of the encoder bridge unit 30 changes the operationconditions of the converter 10 based on the channel adaptive controlsignal indicating the operation conditions (Step S113). For example,when the transmission delay time D1 is excessively long and thereproduction delay time U is made longer in accordance with thetransmission delay time D1, reproduction time at the speaker 61 and thedisplay unit 58 becomes delayed excessively. As a result, there is alimit to making the reproduction delay time U longer. In view of this,the channel adaptive controller 27 not only causes the encoder bridgeunit 30 to change the reproduction delay time U to be the reproductiondelay time U′ but also causes the converter 10 to decrease the framerate of video (sound) data and to decrease the resolution of video(sound) data, thereby addressing the congestion of the communicationnetwork 9. This causes the encoder bridge unit 30, as with Step S103, toadd the current time information (T₀) to the video (sound) data [A] as atime stamp in accordance with the changed operation conditions (StepS104). The video (sound) data is thus added (Step S114). Thetransmitter/receiver 31 transmits the video (sound) data and the timeinformation (T₀) of the distribution control system 2 to thetransmitter/receiver 51 of the communication terminal 5 (Step S115). Thetransmitter/receiver 51 of the communication terminal 5 receives thevideo (sound) data and the time information (T₀) of the distributioncontrol system 2 and outputs the video (sound) data and the timeinformation (T₀) to the reproduction controller 53.

In the communication terminal 5, based on the reproduction delay timeinformation (U′) acquired at Step S112, the time information (T₀)acquired at Step S115, and the time difference information (Δ) stored inthe storage unit 5000 at Step S88, the reproduction controller 53 waitsuntil the time (T₀+U′−Δ) in the communication terminal 5 and thenoutputs the video (sound) data to the decoding unit 50, thereby, as withStep S105, causing the speaker 61 to output sound and the display unit58 to reproduce video through the rendering unit 55 (Step S116). This isfollowed by the processing at and after Step S106. Thus, the processingof the downstream channel adaptive control is performed continuously.

Processing of Upstream Channel Adaptive Control

Described next with reference to FIG. 21 is the processing of channeladaptive control on data transmitted from the communication terminal 5to the distribution control system 2 (upstream). FIG. 20 is a sequencediagram illustrating the processing of channel adaptive control on datatransmitted from the communication terminal to the distribution controlsystem.

First, the encoding unit 60 of the communication terminal 5 encodescontent data as video (sound) data [E] input from the camera 62 and themicrophone 63 (Step S121). In this situation, the encoding unit 60acquires the time information (t₀) indicating the current time t₀ in thecommunication terminal 5 and the time difference information (Δ)indicating the time difference Δ from the storage unit 5000 and does notencode them. The transmitter/receiver 51 transmits the video (sound)data [E], the time information (t₀), and the time difference information(Δ) to the transmitter/receiver 31 of the distribution control system 2(Step S122). The transmitter/receiver 31 of the distribution controlsystem 2 receives the video (sound) data [E], the time information (t₀),and the time difference information (Δ).

In the distribution control system 2, the decoding unit 40 reads time T₀indicating when the video (sound) data [E] and the like were received atStep S112 from the time management unit 25 (Step S123). The decodingunit 40 then calculates transmission delay time d1 indicating time fromthe point when the video (sound) data is transmitted from thecommunication terminal 5 to the point when it is received by thedistribution control system 2 (Step S124). This calculation is performedby Equation (4) below; when the communication network 9 becomescongested, the transmission delay time d1 becomes longer.d1=T ₀−(t ₀+Δ)  (4)

As is the case with the delay information acquisition unit 57, the delayinformation acquisition unit 37 a of the distribution control system 2acquires transmission delay time information (d1) indicating thetransmission delay time d1 from the decoding unit 40 and holds it for acertain period of time, and when a plurality of pieces of transmissiondelay time information (d1) are acquired, outputs to the channeladaptive controller 37 b the transmission delay time information (d)indicating frequency distribution information based on a plurality ofpieces of the transmission delay time d1 (Step S125).

Based on the transmission delay time information (d), the channeladaptive controller 37 b calculates the operation conditions of theencoding unit 60 (Step S126). The transmitter/receiver 31 transmits achannel adaptive control signal indicating the operation conditions suchas a frame rate and data resolution to the transmitter/receiver 51 ofthe communication terminal 5 (Step S127). The transmitter/receiver 51 ofthe communication terminal 5 receives the channel adaptive controlsignal. In other words, in the case of the channel adaptive controlillustrated in FIG. 20 (downstream), the channel adaptive control signalis output to the encoder bridge unit 30 within the same distributioncontrol system 2, and in contrast, in the case of the channel adaptivecontrol illustrated in FIG. 21 (upstream), the channel adaptive controlsignal is transmitted to the communication terminal 5 from thedistribution control system 2 through the communication network 9.

Based on the operation conditions received by the transmitter/receiver51, the encoding unit 60 changes the operation conditions of theencoding unit 60 (Step S128). The encoding unit 60 then performs thesame processing as Step S121 based on the new operation conditions (StepS129). The transmitter/receiver 51, as with Step S122, transmits thevideo (sound) data [E] acquired from the camera 62 and the microphone 63and encoded, the time information (t₀) indicating the current time t₀ inthe communication terminal 5 acquired from the storage unit 5000, andthe time difference information (Δ) indicating the time difference Δalso acquired from the storage unit 5000 to the transmitter/receiver 31of the distribution control system 2 (Step S130). Thetransmitter/receiver 31 of the distribution control system 2 receivesthe video (sound) data [E], the time information (t₀), and the timedifference information (Δ). This is followed by the processing at andafter Step S123. Thus, the processing of the upstream channel adaptivecontrol is performed continuously.

Processing of Multidisplay

The processing of multidisplay is described next with reference to FIG.22 to FIG. 24. FIG. 22 to FIG. 24 are sequence diagrams illustrating theprocessing of multidisplay illustrated in FIG. 5.

The following describes an example of reproducing video (sound) [XYZ]being reproduced on the communication terminal 5 a also on thecommunication terminals (5 f 1, 5 f 2, 5 f 3) in a divided manner.

The browser 20 for displaying web content is referred to as a “browser20 a”, and the browser 20 for displaying a setting screen for a user isreferred to as a “browser 20 b”. Described first is the processingcorresponding to Step S30 in FIG. 17.

First, the browser 20 a of the distribution control system 2 renders theweb content data [XYZ] acquired from the web server 8, therebygenerating pieces of frame data as still image (sound) data and outputsthem to the transmission FIFO 24 (Step S201). The converter 10 encodesthe pieces of frame data stored in the transmission FIFO 24, therebyconverting them into video (sound) data [XYZ] in a data formatdistributable to the communication terminal 5 a (Step S202).

The transmitter/receiver 31 transmits the video (sound) data [XYZ]converted by the converter 10 to the transmitter/receiver 51 of thecommunication terminal 5 a (Step S203). The transmitter/receiver 51 ofthe communication terminal 5 a receives the video (sound) data [XYZ] andoutputs it to the reproduction controller 53.

In the communication terminal 5 a, the decoding unit 50 acquires thevideo (sound) data [XYZ] from the reproduction controller 53 and decodesit (Step S204). After that, the speaker 61 reproduces sound based ondecoded sound data [XYZ], and the display unit 58 reproduces video basedon video data [XYZ] acquired from the decoding unit 50 and rendered bythe rendering unit 55 (Step S205).

A screen displayed on the display unit 58 is switched to a menu requestscreen (not illustrated) by the user of the communication terminal 5 a,and the operating unit 52 receives the pressing of a “distributiondestination selection menu” (not illustrated) on the menu request screen(Step S206). This causes the transmitter/receiver 51 to transmit arequest for switching to the distribution destination selection menu tothe transmitter/receiver 71 a of the terminal management system 7 (StepS207). The transmitter/receiver 71 a of the terminal management system 7receives the request for switching to the distribution destinationselection menu. This request includes the terminal ID of thecommunication terminal 5 a.

The transmitter/receiver 71 b transmits a startup request of the browser20 b to the transmitter/receiver 21 of the distribution control system 2(Step S208). The transmitter/receiver 21 of the distribution controlsystem 2 receives the startup request of the browser 20 b and issues thestartup request of the browser 20 b to the browser management unit 22.

The browser management unit 22 then starts up the browser 20 b (StepS209). The creating/selecting unit 310 of the encoder bridge unit 30switches the output from the browser 20 a to the converter 10 (e.g., theconverter 10 a) to the output from the browser 20 b to the converter 10(e.g., the converter 10 b) (Step S210). When the communication terminal5 a and another communication terminal 5 (e.g., the communicationterminal 5 b) are sharing the converter 10 (e.g., the converter 10 a) toreceive the video (sound) data at Step S203, the creating/selecting unit310 of the encoder bridge unit 30 newly creates the converter 10 (e.g.,the converter 10 b), because the other communication terminal 5 (e.g.,the communication terminal 5 b) is using the converter 10 (e.g., theconverter 10 a) for the browser 20 a.

The transmitter/receiver 21 transmits a request for a distributiondestination selection menu to the transmitter/receiver 71 b of theterminal management system 7 in accordance with an instruction by thebrowser 20 b (Step S211). In this situation, the terminal ID of thecommunication terminal 5 a is also transmitted. The transmitter/receiver71 b of the terminal management system 7 receives the request for adistribution destination selection menu and outputs the terminal ID ofthe communication terminal 5 a to the storage unit 7000.

In response thereto, the storage unit 7000 of the terminal managementsystem 7 searches the available terminal management table 7020 based onthe terminal ID, thereby extracting the corresponding shared ID (StepS212). This shared ID indicates a communication terminal 5 available forthe communication terminal 5 a to perform remote sharing processing. Asillustrated in FIG. 14, because the terminal ID of the communicationterminal 5 a is “t001”, the shared IDs to be extracted are “v003” and“v006”.

The storage unit 7000 further searches the terminal management table7010 based on the extracted shared ID, thereby extracting display nameinformation indicating the corresponding display name (Step S213). Asillustrated in FIG. 13, the display names corresponding to the extractedshared IDs “v003” and “v006” are “Tokyo head office 10F MFP” and “Osakaexhibition hall IF multidisplay”, respectively.

The transmitter/receiver 71 b transmits distribution destinationselection menu data [M] as content data to the transmitter/receiver 21of the distribution control system 2 (Step S214). Thetransmitter/receiver 21 of the distribution control system 2 receivesthe distribution destination selection menu data [M] and outputs it tothe browser 20 b. As illustrated in FIG. 12, this distributiondestination selection menu data [M] includes check boxes, shared IDs,and display names.

As illustrated in FIG. 23, the browser 20 b renders the content dataindicating the distribution destination selection menu data [M] acquiredfrom the terminal management system 7, thereby generating pieces offrame data as still image (sound) data and outputs them to thetransmission FIFO 24 (Step S221). The converter 10 encodes the pieces ofimage (sound) data [M] stored in the transmission FIFO 24, therebyconverting them into video (sound) data [M] in a data formatdistributable to the communication terminal 5 a (Step S222).

The transmitter/receiver 31 transmits the video (sound) data [M]converted by the converter 10 to the transmitter/receiver 51 of thecommunication terminal 5 a (Step S223). The transmitter/receiver 51 ofthe communication terminal 5 a receives the video (sound) data [M] andoutputs it to the reproduction controller 53.

In the communication terminal 5 a, the decoding unit 50 acquires thevideo (sound) data [M] from the reproduction controller 53 and decodesit (Step S224). After that, the display unit 58 reproduces video asillustrated in FIG. 12 based on the video data [XYZ] acquired from thedecoding unit 50 and rendered by the rendering unit 55 (Step S225).

In the distribution destination selection menu illustrated in FIG. 12,when the check box of the shared ID “v006” is checked and the “OK”button is pressed by the user, the operating unit 52 receives theoperation input by the user (Step S226).

The transmitter/receiver 51 transmits a check result as operation datato the transmitter/receiver 31 of the distribution control system 2(Step S227). The transmitter/receiver 31 of the distribution controlsystem 2 receives the check result as operation data and outputs it tothe browser 20 b.

The browser 20 b selects the shared ID from the check result (StepS228). The transmitter/receiver 21 transmits a request for adding adistribution destination, to the transmitter/receiver 71 b of theterminal management system 7 in accordance with an instruction by thebrowser 20 b (Step S229). This request for adding a distributiondestination includes the shared ID selected at Step S227. Thetransmitter/receiver 71 b of the terminal management system 7 receivesthe request for adding a distribution destination and outputs the sharedID to the storage unit 7000. The browser 20 b then ends (Step S230).This causes the creating/selecting unit 310 of the encoder bridge unit30 to switch the output from the browser 20 b to the converter 10 backto the output from the browser 20 a to the converter 10 (Step S231).

As illustrated in FIG. 24, in the storage unit 7000 of the terminalmanagement system 7, the terminal management table 7010 is searchedbased on the shared ID sent at Step S229, thereby extracting thecorresponding terminal ID and installation position information (StepS241). The transmitter/receiver 71 b transmits an instruction to add adistribution destination, to the transmitter/receiver 21 of thedistribution control system 2 (Step S242). This instruction to add adistribution destination includes the terminal ID and the installationposition information extracted at Step S241. The transmitter/receiver 21of the distribution control system 2 receives the instruction to add adistribution destination and outputs the instruction to add adistribution destination to the browser management unit 22. Includedhere are three sets of the terminal ID and the installation positioninformation, that is, the terminal ID and the installation positioninformation being “t006” and “left”, respectively, the terminal ID andthe installation position information being “t007” and “middle”,respectively, and the terminal ID and the installation positioninformation being “t008” and “right”, respectively.

The creating/selecting unit 310 of the encoder bridge unit 30 creates aconverter 10 for multidisplay (Step S243). In this case, thecreating/selecting unit 310 of the encoder bridge unit 30 acquires theterminal ID and the installation position information from the browsermanagement unit 22.

The dividing unit 13 of the converter 10 created at Step S243 dividesthe pieces of frame data [XYZ] as still image (sound) data stored in thetransmission FIFO 24, and the encoding unit 19 encodes the dividedpieces of frame data (Step S244).

The transmitter/receiver 31 transmits video (sound) data [X] encoded bythe encoder bridge unit 30 to the transmitter/receiver 51 of thecommunication terminal 5 f 1 based on the terminal ID (“t006”) and theinstallation position information (“left”) (Step S245-1). Thetransmitter/receiver 51 of the communication terminal 5 f 1 receives thevideo (sound) data [X] and outputs it to the reproduction controller 53.

In the communication terminal 5 f 1, the decoding unit 50 acquires thevideo (sound) data [X] from the reproduction controller 53 and decodesit (Step S246-1). After that, the speaker 61 reproduces sound based ondecoded sound data [X], and the display unit 58 reproduces video basedon video data [X] acquired from the decoding unit 50 and rendered by therendering unit 55 (Step S247-1).

Similarly, the transmitter/receiver 31 transmits video (sound) data [Y]encoded by the encoder bridge unit 30 to the transmitter/receiver 51 ofthe communication terminal 5 f 2 based on the terminal ID (“t007”) andthe installation position information (“middle”) (Step S245-2). Thetransmitter/receiver 51 of the communication terminal 5 f 2 receives thevideo (sound) data [Y] and outputs it to the reproduction controller 53.

In the communication terminal 5 f 2, the decoding unit 50 acquires thevideo (sound) data [Y] from the reproduction controller 53 and decodesit (Step S246-2). After that, the speaker 61 reproduces sound based ondecoded sound data [Y], and the display unit 58 reproduces video basedon video data [Y] acquired from the decoding unit 50 and rendered by therendering unit 55 (Step S247-2).

Similarly, the transmitter/receiver 31 transmits video (sound) data [Z]encoded by the encoder bridge unit 30 to the transmitter/receiver 51 ofthe communication terminal 5 f 3 based on the terminal ID (“t008”) andthe installation position information (“right”) (Step S235-3). Thetransmitter/receiver 51 of the communication terminal 5 f 3 receives thevideo (sound) data [Z] and outputs it to the reproduction controller 53.

In the communication terminal 5 f 3, the decoding unit 50 acquires thevideo (sound) data [Z] from the reproduction controller 53 and decodesit (Step S246-3). After that, the speaker 61 reproduces sound based ondecoded sound data [Z], and the display unit 58 reproduces video basedon video data [Z] acquired from the decoding unit 50 and rendered by therendering unit 55 (Step S247-3).

Sharing/Division of Encoder

The following can be considered as conditions for causing a plurality ofcommunication terminals 5 to share the encoder (the converter 10):

-   (1) The communication terminals 5 share one browser 20.-   (2) Ranges to be processed (display areas on the communication    terminals 5) for video (sound) from the browser 20 are the same.-   (3) Encoding profiles such as frame rates (bit rates) for video    (sound), distribution cycles, and resolutions are the same.

For example, the condition (1) applies to the case in which video(sound) from one browser 20 is multicast to the communication terminals5. The condition (2) applies to the case in which, when part of thevideo (sound) from the browser 20 is displayed on the communicationterminals 5, their display areas are the same. The condition (3) appliesto the case in which the display capabilities, processing capabilities,or the like of the communication terminals 5 subjected to multicast areequal and the line speeds or the like are equal.

When performing dynamic sharing or division (release of sharing) of theencoder (the converter 10), it is preferable that the user on thecommunication terminal 5 side under distribution does not recognize theswitching of the converter 10. This is because when a setting change onthe decoding unit 50 of the communication terminal 5 is needed for theuser along with the sharing or division of the converter 10, a pause invideo or a blackout may occur, leading to an inability to achieve smoothreproduction of the content.

Among the above conditions (1) to (3) for the sharing of the encoder(the converter 10), the condition (2) has no influence on the encodingprofiles and hence has no influence on the decoding unit 50 of thecommunication terminal 5. The condition (3) has an influence on theencoding profiles and hence has an influence on the decoding unit 50 ofthe communication terminal 5. In view of this, the present embodimentperforms the following control in order to minimize the influence on thedecoding unit of the communication terminal 5.

Bit Rate Change

An influence on buffer management within the decoding unit 50 can beconsidered as an example of influence occurring in the decoding unit 50of the communication terminal 5 when the compression rate of image(sound) data by the converter 10 is changed. Ensuring an extra buffer ofthe decoding unit 50 in advance can minimize the influence on the buffermanagement within the decoding unit 50.

Frame Rate Change

In the present embodiment, for example, the upper limit value of theframe rate is defined to be an integral multiple of variable rangevalues. A physical frame rate is always fixed to its upper limit value.Given this situation, the use of a skip frame can change the logicalframe rate of the converter 10 in the encoder bridge unit 30 of thedistribution control system 2.

FIG. 25 is a diagram for illustrating an example of frames distributedwhen the converter 10 is switched so as to decrease the frame rate. InFIG. 25, the frame rates of the converters 10 a and 10 b are assumed tobe, for example, 30 fps. As illustrated in FIG. 25, the converter 10 boutputs frames with the same frame rate (30 fps) as the converter 10 a,with half the frames being skip frames (S frames). This reduces thelogical frame rate by the converter 10 b to 15 fps, which is half theframe rate (30 fps) of the converter 10 a.

FIG. 26 is a diagram for illustrating an example of frames distributedwhen the converter 10 is switched so as to increase the frame rate. FIG.26 illustrates a case of using the converters 10 a and 10 b having thesame frame rate as FIG. 25. As illustrated in FIG. 26, in contrast tothe case illustrated in FIG. 25, the converter 10 is switched from theconverter 10 b to the converter 10 a, thereby increasing the frame ratefrom 15 fps to 30 fps.

Thus, one frame in several generated frames is replaced with a skipframe (S frame), thereby decreasing the substantial frame rate. Thisenables distribution with a frame rate suitable for the line speed ofthe communication terminal 5.

Change in Resolution

When a resolution is changed, the decoding unit 50 of the communicationterminal 5 is needed to be reset. When the decoding unit 50 is reset,the buffer therewithin is cleared, which may cause a pause in video or ablackout.

In view of the above, the present embodiment changes a logicalresolution without changing a physical resolution. The logicalresolution changed here is not the resolution of a screen the browser 20includes as software, but the resolution of an image (still image)output by the browser 20.

Main Effects of the Embodiment

As described above with reference to the specific example, in thedistribution system 1 according to the present embodiment, thedistribution control system 2 includes the browser 20 that performsrendering and the encoder bridge unit 30 that performs encoding and thelike in the cloud. The browser 20 generates pieces of frame data asstill image (sound) data based on content data described in a certaindescription language. The encoder bridge unit 30 converts the pieces offrame data into video (sound) data distributable through thecommunication network 9. After that, the distribution control system 2distributes the video (sound) data to the communication terminal 5. As aresult, the communication terminal 5 can smoothly reproduce web contentwithout update of its browser or time and costs for upgrading thespecifications of a CPU, an OS, a RAM, and the like. This eliminates theproblem in that enriched content increases a load on the communicationterminal 5.

In particular, the browser 20 enables real-time communication, and theconverter 10 performs real-time encoding on the frame data generated bythe browser 20. Consequently, unlike a case in which a DVD playerselects and distributes non real-time (that is, pre-encoded) video(sound) data as seen in, for example, on-demand distribution of video(sound) data, the distribution control system 2 renders content acquiredimmediately before being distributed, thereby generating pieces of framedata and then encoding them. This allows real-time distribution of video(sound) data.

Supplementary Description

The distribution system 1 according to the present embodiment includesthe terminal management system 7 and the distribution control system 2as separate systems. For example, the terminal management system 7 andthe distribution control system 2 may be constructed as an integralsystem by, for example, causing the distribution control system 2 tohave the functions of the terminal management system 7.

The distribution control system 2 and the terminal management system 7according to the above embodiment may be implemented by a singlecomputer or may be implemented by a plurality of computers in whichindividual parts (functions, means, or storage units) are divided andassigned in any desirable unit.

Storage media such as CD-ROMs and HDDs in which the programs of theabove embodiment are recorded can be provided as program productsdomestically or abroad.

One aspect of the present invention can provide a distribution controlsystem, a distribution system, a distribution control method, and acomputer-readable storage medium that can reduce a load on acommunication terminal that uses enriched content even when using thethin client technology.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. A distribution control system, comprising: memorystoring computer-readable instructions; and one or more processorsconfigured to execute the computer-readable instructions such that theone or more processors are configured to perform operations including,generating image data from content data; creating a first converterconfigured to convert the image data into first transmission data for afirst communication terminal from among a plurality of communicationterminals; transmitting the first transmission data to one or more ofthe plurality of communication terminals; and newly creating a converterto be assigned to each of the communication terminals of the pluralityof communication terminals or selecting a converter out of a pluralityof converters already created, such that a common converter is assignedto communication terminals, from among the plurality of communicationterminals, at least one of whose display capability and line speed isequal among the plurality communication terminals, the plurality ofconverters including the first converter, wherein frame data of theimage data is generated from sound data included in the content data orsound data input from a microphone, by rendering the content data, usinga renderer, and the converters of the plurality of converters are aplurality of encoders configured to convert the frame data intotransmission data to be transmitted through a communication network byencoding the frame data, wherein the one or more processors areconfigured to create the first converter such that the first converteris capable of performing conversion appropriate for a capability of afirst communication terminal to reproduce the first transmission data,the first communication terminal being one of the plurality ofcommunication terminals, wherein the one or more processors areconfigured to create the plurality of converters such that a totalnumber of the plurality of converters is based on a total number ofpieces of the content data, and wherein the one or more processors are,configured to use a converter that is already created for a firstcommunication terminal without creating a new converter for a secondcommunication terminal, from among the plurality of communicationterminals, in starting distribution to the second communication terminalin addition to distribution to the first communication terminal, when,the distribution control system distributes a same transmission data tothe second communication terminal as transmission data being distributedto the first communication terminal, and the second communicationterminal has a same capability as a capability of the firstcommunication terminal to reproduce the first transmission data, andconfigured to create a second converter that is configured to convertthe image data into second transmission data for the secondcommunication terminal, when, the distribution control system does notdistribute a same transmission data to the second communication terminalas transmission data being distributed to the first communicationterminal, or the second communication terminal does not have a samecapability as a capability of the first communication terminal toreproduce the first transmission data.
 2. The distribution controlsystem according to claim 1, wherein, when a communication terminal,from among the plurality of communication terminals, becomes a changedterminal, the one or more processors are configured to newly create aconverter for the changed communication terminal or to select, for thechanged communication terminal, a different converter out of theplurality of converters already created, the changed communicationterminal being a terminal whose display capability or line speed haschanged.
 3. The distribution control system according to claim 1,wherein and the one or more processors implement a web browser, and thefirst converter includes a first encoder configured to perform encodingon frame data generated by the web browser.
 4. The distribution controlsystem according to claim 3, wherein, the one or more processors areconfigured such that the web browser enables real-time communication,and the first encoder is configured to perform real-time encoding on theframe data generated by the web browser.
 5. The distribution controlsystem according to claim 4, wherein the first encoder is configured toperform trimming or resizing and then encoding on the frame datagenerated by the web browser.
 6. The distribution control systemaccording to claim 5, wherein the first encoder is configured to performtrimming, resizing, dividing, and then encoding.
 7. The distributioncontrol system according to claim 1, wherein the one or more processorsare configured to generate a skip frame as null data in place of a frameof the first transmission data in accordance with a degree of decreasinga frame rate, when decreasing a frame rate in accordance with line speedof the communication terminal.
 8. A distribution system, comprising: thedistribution control system according to claim 1; and the plurality ofcommunication terminals.
 9. A distribution control method comprising:generating image data from content data; creating a first converterconfigured to convert the image data into first transmission data for afirst communication terminal from among a plurality of communicationterminals; transmitting the first transmission data to one or more ofthe plurality of communication terminals; and newly creating a converterto be assigned to each of the communication terminals of the pluralityof communication terminals or selecting a converter out of a pluralityof converters already created, such that a common converter is assignedto communication terminals, from among the plurality of communicationterminals, at least one of whose display capability and line speed isequal among the plurality of communication terminals, the plurality ofconverters including the first converter, wherein frame data of theimage data is generated from sound data included in the content data orsound data input from a microphone, by rendering the content data, usinga renderer, and the converters of the plurality of converters are aplurality of encoders configured to convert the frame data intotransmission data to be transmitted through a communication network byencoding the frame data, wherein the one or more processors areconfigured to create the first converter such that the first converteris capable of performing conversion appropriate for a capability of afirst communication terminal to reproduce the first transmission data,the first communication terminal being one of the plurality ofcommunication terminals, wherein the one or more processors areconfigured to create the plurality of converters such that a totalnumber of the plurality of converters is based on a total number ofpieces of the content data, and wherein the one or more processors are,configured to use a converter that is already created for a firstcommunication terminal without creating a new converter for a secondcommunication terminal, from among the plurality of communicationterminals, in starting distribution to the second communication terminalin addition to distribution to the first communication terminal, when,the distribution control system distributes a same transmission data tothe second communication terminal as transmission data being distributedto the first communication terminal, and the second communicationterminal has a same capability as a capability of the firstcommunication terminal to reproduce the first transmission data, andconfigured to create a second converter that is configured to convertthe image data into second transmission data for the secondcommunication terminal, when, the distribution control system does notdistribute a same transmission data to the second communication terminalas transmission data being distributed to the first communicationterminal, or the second communication terminal does not have a samecapability as a capability of the first communication terminal toreproduce the first transmission data.
 10. A distribution controlsystem, comprising: memory storing computer-readable instructions; andone or more processors configured to execute the computer-readableinstructions such that the one or more processors are configured toperform operations for distributing content data to a plurality ofcommunication terminals, each of the plurality of communicationterminals having a corresponding transmission attribute that includes atleast one of a type of the content data being received by thecommunication terminal and a line speed of a communications path throughwhich the communication terminal receives the content data, theoperations including, generating image data from the content data;generating, based on a first transmission attribute, a first encoder,the first transmission attribute being the transmission attributecorresponding to a first communication terminal from among the pluralityof communication terminals, generating first transmission data byencoding the image data using the first encoder, generating a comparisonbased on the first transmission attribute and a second transmissionattribute, the second transmission attribute being the transmissionattribute corresponding to a second communication terminal from amongthe plurality of communication terminals, selecting, based on thecomparison, between generating, based the second transmission attribute,a second encoder different from the first encoder, and generating secondtransmission data by encoding the image data using the second encoder,and converting the image data into second transmission data using thefirst converter without generating the second encoder, transmitting thefirst transmission data to the first communication terminal, andtransmitting the second transmission data to the second communicationterminal.
 11. The distribution control system of claim 10, wherein theone or more processors are configured to generate the first encoderincludes by selecting encoding attributes of the first encoder such thatthe first transmission data generated by the first encoder correspondsto a content reproduction capability of the first communication device,the content reproduction capability of the first encoder being indicatedby the first transmission attribute.
 12. The distribution control systemof claim 11, wherein the one or more processors are configured togenerate the second encoder by selecting encoding attributes of thesecond encoder such that the second transmission data generated by thesecond encoder corresponds to a content reproduction capability of thesecond communication device, the content reproduction capability of thesecond encoder being indicated by the second transmission attribute.